Table 1.
Histone variant genes, proteins, and functions in Arabidopsis thaliana
| Histone variants | Arabidopsis Genes | ArabidopsisLoci | Protein | Chaperones/remodelers | Function | Knockout/knockdown Arabidopsis phenotype | Modification | ||
|---|---|---|---|---|---|---|---|---|---|
| General | development | Stress responses | |||||||
| H3.3 | HTR4 HTR5 HTR8 |
At4g40030 At4g40040 At5g10980 |
H3.3 H3.3 H3.3 |
HIRA (95) ATRX(33) |
Transcriptional activation (123, 127, 144, 156) | Flowering time(156); Male Gametogenesis (54)); Post-germination development (5); Cell proliferation and organogenesis (101) |
Regulate the expression of responsive and hypervariable genes(145) | htr5/htr8, are phenotypically normal ; Triple mutants cause lethality; htr4/htr4;htr8/htr8 plants that carried either amiR-HTR5-I or amiR-HTR5-II (h3.3kd) exhibit leaf serration, incomplete sterility, and growth defects (145) | H3.3K36me3 (89) |
| H2A.Z | HTA8 HTA9 HTA11 |
At2g38810 At1g52740 At3g54560 |
H2A.Z.8 H2A.Z.9 H2A.Z.11 |
SWR1 complex (42, 137) | transcriptional activation and repression | Flowering time (16, 29, 86, 98, 124); vegetative to reproductive phase transition (42, 148); Inflorescence architecture (11); Germline development (157); Circadian clock (133) | Temperature response (24, 66, 132); Phosphate deficiency (40, 126, 151) Drought stress (11, 128); Immunity (6); Salt stress (93) |
Double/ triple mutants show developmental aberrations (83, 94); Triple mutants are viable but show reduced fertility (20); Knockdown of all three H2AZ genes cause early flowering (16) |
H2A.Z acetylation (25); H2A.Z monoubiquitination (H2A.Zub) (44); H2A.Z SUMOylation and methylation? |
| H2A.X | HTA3 HTA5 |
At1g54690 At1g08880 |
H2A.X.3 H2A.X.5 |
FACT? (45) | DNA damage response (13, 67, 112); transcription activation (146) | H2A.X is unessential for Arabidopsis development (50) | genotoxic stress(141) | The single/ double mutants are viable, fertile and indistinguishable from wild type (50) | phosphorylated H2A.X (67, 112) |
| H2A.W | HTA6 HTA7 HTA12 |
At5g59870 At5g27670 At5g02560 |
H2A.W.6 H2A.W.7 H2A.W.12 |
DDM1 (100) | Chromatin condensation (150) | H2A.W is unessential for Arabidopsis development (10) |
Not determined | H2A.W triple mutants are indistinguishable from the wild type (10) | phosphorylated H2A.W (75, 112) |
| H1 | HON1 HON2 HON3 |
At1g06760 At2g30620 At2g18050 |
H1.1 H1.2 H1.3 |
NRP1 and NRP2?(91, 102) | Chromatin condensation (14, 114) | Flowering time, Seed dormancy, Lateral root, Stomata and callus development (114) male and female gametogenesis (120) |
Drought stress (2) Combined light and water deficiency (116) |
Triple mutants are viable but show extended dormancy, early flowering, increased root density and lateral root numbers, and altered stomata pattern (114) | phosphorylation, acetylation, mono- and dimethylation, formylation, ,crotonylation and propionylation (64) |